Anecdotal reports have brought attention to underinsured patients who restrict their use of medications because of cost.2–4
However, surprisingly little research has assessed the frequency of this behavior, which patients are at the highest risk of medication restriction, and how prescription coverage may modify this risk. Our findings quantify and clarify these relationships. Among seniors with no prescription coverage, medication restriction is common in several vulnerable populations, including ethnic minorities, the poor, the sick and frail, and those with high out-of-pocket drug costs. In contrast, seniors in these high-risk groups who had partial or full prescription coverage were much less likely to restrict their use of medications.
Several of these findings bear further examination. Low income and high out-of-pocket drug costs both play an important role in medication restriction, consistent with basic economic principles. However, the strong association between minority ethnicity and medication restriction was unexpected. This association persisted after adjustment for out-of-pocket drug costs, income, health status, and other risk factors, suggesting that minority patients may be more predisposed to medication restriction when confronted with prescription costs for which they lack insurance. Part of this association may be due to unmeasured economic factors. However, interethnic differences in attitudes and behaviors toward medical decisions, reflecting different experiences with the health care system, may also play a role.13–15
As a result, minority elders may prioritize prescription drug spending differently than whites in the face of competing economic concerns, including such necessities as food and shelter. Whatever the cause, this high risk of medication restriction was very sensitive to prescription coverage, with rates of restriction dramatically lower among minorities who had prescription coverage than in those who lacked it.
Similar factors may also explain why out-of-pocket prescription drug costs, the presumed main causal mechanism linking prescription coverage to medication restriction, only partially explained the relationship between prescription coverage and medication restriction even after adjustment for income, ethnicity, and other variables. Some of the residual association may be due to imprecision of the drug cost variable we used. However, it may be that people with prescription coverage have greater personal investment in the health care system, and that subsidized drug costs make patients more willing to pay their share for medications even if their total out-of-pocket expenditures are equal to patients receiving no such help.
Although scant research has directly addressed medication restriction due to cost, other related studies support our findings. A report from the 1997 National Health Interview Survey found increased rates of medication restriction in Medicare patients who lacked prescription coverage.9
Studies of Medicare beneficiaries show consistently less prescription drug use among patients who lack prescription coverage than among those with coverage.5–8,16,17
These disparities, which are more pronounced in the sickest and poorest patients, have grown in recent years. Overall, those who lack prescription coverage receive 30% fewer prescriptions, yet have nearly twice the out-of-pocket costs, than those with coverage.6,7
Similar associations between medication cost and use have been found with medication copayments.18,19
The effect of medication restriction on the health and welfare of individual patients, and on total health system spending, remains incompletely defined. However, policies designed to limit medication use may have serious consequences for patients' health, resulting in increased emergency department visits, nursing home admissions, use of emergency mental health services, and more.20–24
Further, drug costs savings from such policies can be offset by increased utilization of other health services due to patient underuse of essential medications.1,20,24–27
High drug costs and lack of prescription coverage may have additional consequences. Doctors who know their patients cannot afford high prescription costs may be less likely to prescribe costly but effective medications. Moreover, medication expenses comprise a substantial proportion of the 19% of elderly people's income that is spent on health care, imposing a particularly heavy burden on the poor.9,28,29
As a result, many low-income elderly may be forced to choose between their medications and food, clothing, or telephone service.2
In this way, even those elders who do not restrict their use of medications may be forced to forego other goods and services important to their well-being.
The risk factors for medication restriction that we identified would be less important were they not so common. Half of all Medicare enrollees lack a consistent source of prescription coverage,30
and a disproportionate share of the uncovered live below the poverty line.6
Out-of-pocket prescription drug costs exceeded $100 per month in over one quarter of the elderly subjects with no prescription coverage that we surveyed in 1995–1996. Since the time of the survey, prescription drug expenses have approximately doubled,1
and prescription coverage options have declined for many seniors.9,31
Several methodologic considerations may affect interpretation of this study. Because medication restriction was assessed by self-report, it is subject to questions of validity (i.e., systematic misreporting) and bias (i.e., differential reporting by one group compared with another). We believe the question used in this study has good face and construct validity for the measurement of medication restriction, but we have no data to directly measure the accuracy of this question and the responses it generated. Other studies that have compared patient recall with medical record review document a wide range of accuracy in recalling the use of specific medications and health services.32–36
A handful of studies that examined the effect of socioeconomic factors such as income, education, and race on the accuracy of recall have produced mixed results.33,35,37–41
Thus, while we cannot rule out systematic misreporting of medication restriction, the tendency to underrepresent socially undesirable activities and forget remote events suggests that, to the extent that our data is inaccurate, we likely underestimated the true level of medication restriction.37,38
In addition, while little is known about differential reporting between traditionally disadvantaged versus advantaged groups, the effect would have to be very large to account for the magnitude of differences that we found.
Several other considerations are worth noting. Information on prescription coverage status was also assessed by self-report, the reliability of which has not been fully determined.17,42
Subjects were not provided a standard definition to classify their level of prescription coverage. Also, frequent changes in prescription coverage in the elderly suggests that some subjects with one level of coverage at the time of the survey may have had a different level of coverage in the recent past.6,9
Unmeasured variables, such as depression and personal investment in the health care system, may account for some of the variance in rates of medication restriction. Because medication restriction was assessed in a yes/no format, we could not assess the degree of restriction, nor could we assess the number and types of medications used. Finally, the cross-sectional design precludes us from inferring a causal link between lack of prescription coverage and medication restriction.
The association between prescription coverage and medication restriction, particularly in certain high-risk groups, has important implications for both clinicians and policymakers. Physicians should be alert to the possibility of medication restriction among their elderly patients with no insurance, particularly minority patients and those with low income or high out-of-pocket drug costs. Asking about the impact of medication costs can help physicians identify patients who could benefit from government assistance, industry programs for the medically indigent, or the selection of less-expensive therapeutic alternatives. However, the scope of this problem among vulnerable seniors calls for a broader solution.1
A more comprehensive coverage plan, and policies that limit medication costs, may help reduce medication restriction and with it the clinical, economic, and social morbidity that disproportionately affects our most vulnerable seniors.